From recent tweets (2021-06-22)

The first lot of Stack-chan PCB board has arrived from AllPCB. 

https://www.allpcb.com/

ALLPCB offers a free coupon every month for a small (5pcs) lot. I recommend to use it for the first design trial.

I used KiCad designing board layout and exporting gerber data.

And my one is...successful ;)